[Drug-induced pulmonary interstitial disease]

Patient 1, a 72-year-old man, was admitted with a history of flu-like symptoms and dry cough for three weeks and exertional dyspnea. Prophylactic antibiotic treatment with nitrofurantoin (100 mg/day) had been given for one year for renal calculi. Patient 2, a 64-year-old man, was admitted with increasing dyspnea at rest. He was known to have several cardiological disorders, including episodes of ventricular tachycardia, for which he had been on amiodarone (200 mg/d) for 8 years. Both patients were in reduced general state of health.

In both patients the pO(2) was 68 mm Hg, in Patient 1 while breathing ambient air, in Patient 2 while breathing oxygen (15 l/min). Chest X-ray revealed bronchiectatic infiltrative changes bilaterally in the middle and lower lung fields in Patient 1. High-resolution computed tomography showed massive generalized interstitial infiltrates in the lung of Patient 2.

Nitrofurantoin and amiodarone, as potential causes of the pulmonary changes, were discontinued while steroid treatment was begun. This quickly resulted in improvement of symptoms and clinical findings.

Drug induced pathogenesis has to be taken into account in the differential diagnosis of interstitial lung diseases. A causal association with the administered drugs is often difficult to establish. If suspicion is strong, treatment should be discontinued (replacement by a drug from another class). Depending on severity of clinical symptoms corticosteroids should also be given.